Despite all the texting, though, the 13 Reasons Whyproducer and "Starboy" singer haven't officially defined their relationship yet, the insider said: "As of now, they are just having fun and enjoying each other."

A second insider explained that neither pop star is looking to jump into a serious relationship right now. "Selena was focusing on getting herself back together and The Weeknd was just getting out of a relationship, plus putting out his new album."

Still, their chemistry is undeniable. "He thinks she is extremely talented and sexy," the source said. "They are taking things slow and getting to know each other."